// Copyright 2018 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "src/thread-id.h"
#include "src/base/lazy-instance.h"
#include "src/base/platform/platform.h"

namespace v8 {
namespace internal {

    namespace {

        DEFINE_LAZY_LEAKY_OBJECT_GETTER(base::Thread::LocalStorageKey, GetThreadIdKey,
            base::Thread::CreateThreadLocalKey())

        std::atomic<int> next_thread_id { 1 };

    } // namespace

    // static
    ThreadId ThreadId::TryGetCurrent()
    {
        int thread_id = base::Thread::GetThreadLocalInt(*GetThreadIdKey());
        return thread_id == 0 ? Invalid() : ThreadId(thread_id);
    }

    // static
    int ThreadId::GetCurrentThreadId()
    {
        auto key = *GetThreadIdKey();
        int thread_id = base::Thread::GetThreadLocalInt(key);
        if (thread_id == 0) {
            thread_id = next_thread_id.fetch_add(1);
            CHECK_LE(1, thread_id);
            base::Thread::SetThreadLocalInt(key, thread_id);
        }
        return thread_id;
    }

} // namespace internal
} // namespace v8
